Fix performance issues on query over orderId (fix #2114)

BTCPayServer.Data/Migrations/20201208054211_invoicesorderindex.cs

@@ -0,0 +1,26 @@
+using BTCPayServer.Data;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace BTCPayServer.Migrations
+{
+    [DbContext(typeof(ApplicationDbContext))]
+    [Migration("20201208054211_invoicesorderindex")]
+    public partial class invoicesorderindex : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateIndex(
+                name: "IX_Invoices_OrderId",
+                table: "Invoices",
+                column: "OrderId");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropIndex(
+                name: "IX_Invoices_OrderId",
+                table: "Invoices");
+        }
+    }
+}

BTCPayServer.Data/Migrations/ApplicationDbContextModelSnapshot.cs

@@ -228,6 +228,8 @@ namespace BTCPayServer.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("OrderId");
+
                     b.HasIndex("StoreDataId");
 
                     b.HasIndex("Id", "CurrentRefundId");